一种基于饱和铁心型超导限流器的混合直流限流电路的研究

基于电压源型换流器的高压直流输电系统的故障电流幅值大、上升速度快，现有直流断路器的故障电流开断容量和开断速度受到很大挑战。提出一种基于饱和铁心型超导限流器的混合直流限流电路，利用饱和铁心型超导限流器及限流电阻共同作用实现阻感复合限流，并借助吸能电阻达到加速故障电流清除、缓解直流断路器开断压力的目的。根据直流故障暂态特性，结合该混合直流限流电路与混合式直流断路器的配合策略，分阶段对该混合直流限流电路的工作原理进行理论解析。通过数学推导给出所提混合直流限流电路的参数设计原则。最后，在PSCAD/EMTDC仿真平台中对所提混合直流限流电路的原理正确性和功能有效性进行验证。结果表明，所提混合直流限流电路能有效抑制故障电流、缩短故障线路隔离时间、减少避雷器吸能并能实现饱和铁心型超导限流器快速恢复。

Research on an SI-SFCL-based hybrid DC current-limiting circuit

The fault current of a voltage source converter-based high voltage direct current (VSC-HVDC) system has the characteristics of high amplitude and fast-rising speed. Therefore, the available hybrid DC circuit breaker (HDCCB) faces great challenges in breaking capacity and breaking speed. A saturated iron-core superconducting fault current limiter-based hybrid DC current-limiting circuit (SI-SFCL-HDCCLC) is proposed. This uses the saturated iron-core superconducting current limiter and current-limiting resistor to realize the resistive-inductive compound current-limiting. It also uses an energy absorbing resistor to accelerate the fault current clearing and relieve the breaking pressure of the HDCCB. This paper introduces the working principle of the SI-SFCL-HDCCLC theoretically in stages in combination with the coordination strategy of the proposed SI-SFCL-HDCCLC and hybrid HDCCB (HDCCB) based on the transient characteristics of a DC fault. Then the principles of the parameter design of the SI-SFCL-HDCCLC are analyzed with mathematical derivation. Finally, the theoretical correctness and functional effectiveness of the proposed SI-SFCL-HDCCLC are validated in a PSCAD/EMTDC based environment. The simulation results indicate that the proposed SI-SFCL-HDCCLC combined with HDCCB can effectively suppress fault current, shorten the isolation time of the fault line, reduce the energy absorption of the arrester and realize the rapid recovery of the SI-SFCL.This work is supported by the National Natural Science Foundation of China (No. 52107023).